Retreading mold



Mar. 5,' 1929;

k. K. A. THoRsr-:N

Original Filed June 14, 1926 RETREADING MoLn 2 sheets-sheet 1 INVENTOR IK. KA i-harsen AT oRNEY Mar.' 5, 19z9.. l

K. K. A. THoRsE-N RETREADING iMOLD l2 Sheets-Sheet Original Filed June14, 1926.

INVENTOR K. KJDnThorsen ATT RNEY Patented Mar. 5., 1929.

UNITED STAT KARL K. A. THORSEN, F SAN FRANCISCO, CALIFORNIA.

RETREADING MOLD;

Application led .Tune 14:,v 1926, Serial No. 115,758. Renewed October20, 1928.

This invention relates to improvements in vulcanizing machines,particularly machines for retreading pneumatic tire casings.

. One of the purposes of. the invention is to do away with theobjectionable bead rings now commonly used in vulcanizing machines.These rings often become heated to the extent that they damage the beadsandsides of the ."casing and for this reason are objectionable.

rlhe present invention provides a novel and elficaciousfgrm of supportfor an air bag to be contained within the casing, which support insuresthe holding of the airbag in proper position to properly distend thecasing and in addition vcauses the sidesand bead portions of the tire tobe disposed in proper y position 4Without subjecting such portions tothe damaging eifect of the curing heat.

Another object of the invention is to provide a vulcanizing machine ofthe character described which applies the curing heat to the treadportion only and not to the sides and beads of the `tire and which inone operation will cure the entire tread.

Another object of the invention is to provide a vulcanizing machinewhich will be simple and inexpensive as to construction and reliable andinexpensive as to operation.

Another object of the invention is to `pro vide a novel formof clampingmeans for holding the sectional vulcanizing chamber in proper positionand for clamping the air bag claims hereto appended;

ing any ofthe advantages of the invention.

Referring to the drawings:

Fig. 1 represents a front elevation of the vulcanizing machine of myinvention. Fig. 2 represents a side elevation of the machine.

l Fig. 3 represents a. vertical sectional view of the machine. Y"15P-ig.4 represents a side elevation of the tire casing showing the air bag`ipportin'g.

means therein.

Fig. 5 represents a vertical sectional view of the air bag support.

Flg. 6 represents a side elevation of the matrix.

Fig. 7 represents an 'end viewof the matrix. j The embodiment of theinvention shown in the accompanying drawings comprises an annularvulcanizing shell made up of a stationary section 1 and a hinged section2 which has a flange 3 adapted to telescope .within the sectlon 1,-saidsection 2 being hinged as at 4 to -the side ofthe section l. These twosections are shaped to providev an annular chamber which is circular incross section and adapted to receive an annular matrix 5 which willcontain the tire casing to be vulcanized as shown at 6. The section 1 isformed with an annular steam 'chamber 7 which is rectangular in crossvsection and of suchshape and arrangement as to apply the heat directlyto the tread of the tire instead of to the sides thereof. The lower sideof this chamber communicates with aboiler chamber 8 formed in the basemember 9 of the machine. Water is delivered to the chamber through asuitable feed pipe having connection with a source of water supply, notshown. On top of the machine in communication with the steam -ack-et isa steam gage 11. Beneath the boiler chamber is a suitable burner 12 forheating the water to generate the steam.

. The matrix 5 is formed in two sections hinged together as at 13 atcertain ends and provided withl a lap joint fastening meansgenerally'designated 14 at their other ends. The two sections 1 and 2vof the vulcanizing chamber when closed, provide forl a snug fit ofthematrix therein. The outer side of the flange 3 is beveled and engages abeveled face 15 on the section 1 of the vulcanizing chamber. The outeredgeof the flange abuts a shoulder 16 on the section 1. This provides,for a snug fitting of the two sections together and the proper clampingofthe matrix inthe vulcanizing chamberV so Ias to insure an' ef fectivetransmission .of -heat in the curing operatlon. An air bag or tube 17 ofa one-piece clrcular form like the ordinary inner tube,-is adapted to beplaced within the tire casing 6, in order to hold the walls of thecasing 'distended and in proper position for the vulcanizing operation.This air bagis held in position by means of a sectional ring-like holdermade up of two split-ring sections designated 18 and 19, which sectionsare inserted into the casing so as to properly support the air bag andto hold the lower edges or sides of the casing in proper position.

The section 18 comprises a flat body portion 2O having on one edge anoutwardly extending ilange 21 and on its other edge an inwardlyextending flange 22. On the flange 22 at spaced points, are aperturedears 23 which facilitate the attachment of -a contracting tool, notshown, which tool is employed to contract the split section in grderthat it may be inserted in the tire casing. The split ring. or section19 comprises an annular body -24 wider than the body 20 and provided onone edge with an outwardly extending annular flange 25 corresponding tothe Harige 21. An inwardly extending flange 26 corresponding to the one22 is provided at a point intermediate of the edges of the body and isIadapt-ed to be engaged by the flange 22. On this' liange 26areapertured ears 27 for the same purpose as the ears 23. When thesering sections are assembled in the tire, the body 20 lies against theinner side of the body 24 with one edge of the body 24 engaging theflange 21, thus providing a rimlike holder which properly supports theair bag and in which the rim-like flanges engage the inner sides of thetire casing and hold the tire casing in the proper position as shown inFig. 3. The two inwardly extending iianges 22 and 26 project through theopening on the inner side of the tire casing and into the circular spacecentrally of the vulcanizing chamber in order that they may be clampedand held in position.

As a means for holding the two sections 1 and 2 together I provide aplurality of lag bolts 27 hinged as at 28 on the stationary section 1and adapted to be engaged in. bifurcated ears 29 on the perimeter of thehinged section`2. Thumb screws 30 are mounted on said bolts so as toclamp the two sections together. In addition to this means there areprovided resilient, bowed clamping bars 30 which are hinged at certainends as at 31 to the inner perimeter of the stationary Section 1 andhave apertured ears at their free ends, which ears are adapted to engagein the bifurcatcd apertured ears 33 on the inner perimeter of the hingedsection 2. When the apertures of these ears are in alignment, pins 34are inserted therethrough to hold the clamping bars 30 in place. Theclamping bars 30 are provided with screwy threaded openings 35between'the ends thereof, in which openings screws 36 are mounted so asto extend at right angles to the clamping bars; The outer ends of'thesescrews have ,hand wheels 37 to facilitate the adjustment of the screws.The inner ends of the screws are swivelly connected with bifurcatedclamps 38 which receive in the bifurcations thereof, the flanges 22 and26 of the air bag support. By tightening these clamps the properpressure is exerted on the air bag holder to insure the properpresentation and holding of the tire casing in position to beeffectively vulcanized..

lVith the machine of my invention it is unnecessary to employ the beadrings which are usually required in vulcanizing machines.

Bead rings are usuall of lieav iron and fre- D Aqueiitly become so hotas to burn or damage the beads. I eliminate this objection by providingthe special air bag holder which lits inside of the casing and not onlyprovides for the highly desirable use of an air bag instead of a sand orwater bag to hold the tire casing distended, but which itself engagestlie inner sides of the bead portions of the tire casing in such manneras to hold these portions in proper position with relation to the matrixand vulcanizing chamber (sce Fig. 1). This special form of air bagsupport and casing holder is. made particularly leffective bythc simpleand easily operated clamping members 30. These clamping members 30 arelikewise subject to an easy and effective operation to hold the sectionsof the vulcanizing chamber in proper relation. By having the steamljacket extend at right angles to the tread portion and across the treadonly instead of along t-he side of the tire casing, the curing heat isapplied at the point where it is needed and at no other point on thecasing. This heat is evenly applied throughout tlie entire casing andcuring of tlie'rubber in retreading the casing is therefore elfected inone operation.

The matrix is provided with sockets shown I at 40, adjacent thedetachable ends thereof to provide for attachment to the matrix of asuitable contracting tool, not shown, which may lie use d ininstanceswhere pressure is required to clamp the ends of the matrixtogether when the tire is contained in the matrix.

One of the features of vention is the provision for quick and easyassembling and locking of the vulcanizing sections of the machinetogether, it being possible to disassemble said ease and facility.

I claim: i f l l. A retreading mold comprising a vuladvantage of myinsections with equal canizing chamber made up of two annular sectionswhich are hinged together-on one side and adapted to be moved into andout of engagement with one another, said sectionsi being shapedtoprovide when together an annular vulcanizing chamber which issulistantially circular in crosssection, one of said sections onlyhaving a circumferential steam passage therein and the other of saidsections being adapted to telescope in part within the first namedsection and means for clamping the sections together.

`within the tire to hold the same distended 2. A retreading moldcomprising an annular vulcanizing chamber which is substantiallycircular in cross section, a matrix within the chamber adapted toreceive a. tire to be vulcanized, an air bag adapted to be placed withinthe tire to hold the same distended within the matrix and an annular airbag holding member adapted to be mounted within the tire and comprisingtwo split annular sections engaged with one another to form a rim forthe bag, which split sections engage the inner sides of the tire casingand hold thel casing distcnded -adjacent the bead p0rtions and means forsecuring the air bag holding member in position within the tire.

3. Aaetreading mold comprising an annular vulcanizing chamber lwhich issubstantially circular in cross section, a matrix within the chamberadapted to` receive a tire to be vulcanized, an air bag adapted to beplaced within the matrix and an annular air bag holding member adaptedto be mounted within the tire and comprising two split annular sectionsengaged with one another to form .a rim for the bag, which splitsectionsenga e the inner sides of the tire casing and ho d the casingdistended adjacent the bead portions, means for securing the air bag-holding member in positionl within the tire, which means includes barsextending transversely of the vulcanizing chamber on the innerperimeter'thereof, screws adjustably supported in the bars and clampmembers on the screws ada ted to engage said split sections'of the airag holdingr member.

4a A retreadm mold comprising a sectional vulcanizing c amber comprisingtwo annular sections hinged 4to one another and each lar steam passagetherein, a steam boiler dis-- posed beneath said sections and incommunication with said passage,

a burner for saidl steam boiler, a sectional matrixcomprising 4semi-annular portions which are substantially 'circular in cross sectionand hin ed together at certain ends which is adapte to be received insaid chamber and in which matrix a tire to be vulcanized is placed, anair bag within said tire for holding the tire vdistended within thematrix and an air bag ysupport contained within the tire and having aportion thereof projecting-out o f the tire, 'clamping members hinged onthe lnner perimeter of one of the annular vulcanizmg sections, means forattaching Said clamping members to the innerperimeter of the othervulcanizingsection and clamping meanson said last named clamping membersfor engaging the air bag support.

KARL K. A. THORSEN.

